It is conventionally known to arrange service units, so-called PSUs (passenger service units), above the passenger seats (e.g. on the bottom of the overhead baggage compartments) in the passenger cabin of an aircraft. These passenger service units make various service and information functions available to the passengers. For example, reading lamps, flight attendant call buttons instructional signs, and loudspeakers are integrated into the passenger service units. Such passenger service units including informational units are known, among other things, from the German Patent Publication DE 34 26 893 A1.
The previously known passenger service units have included signs or the like that are able to display fixed invariable information to the passengers. For example, such signs usually include a “fasten seatbelt” sign and a “no smoking” sign. Such fixed invariable signs are embodied with printed sign plates or plaques that can be selectively back-lighted in the installed condition in the passenger service unit. The back-lighting is typically provided by incandescent lamps or light emitting diodes (LEDs). In any event, the back-lighting can simply be either switched on or switched off, to selectively display or not display the fixed instruction provided by the respective sign, such as “fasten seatbelt” or “no smoking” in text and/or symbolic images. It is disadvantageous that the instructional content of the signs is not changeable or variable, or if at all, can only be changed by physically exchanging the entire notification module or at least the printed sign plates. As a result, the available display area of the PSU can only be used for selectively displaying the two fixed invariable signs (e.g. “no smoking” and “fasten seatbelt”)
If it is desired to display other or additional informative or entertaining content (for example flight altitude, remaining flight time, connecting flight information, money exchange rates, weather forecasts or reports, etc.), it has been necessary to install relatively complex information systems, such as inflight entertainment (IFE) systems or passenger flight information systems (PFIS). These systems require a very large financial investment by the airline for equipping the aircraft, and comprise relatively heavy components which thus cause a constant weight penalty in the loading of the aircraft. For example, these systems comprise audio and video tape players or reproducers, cassette stowage units, and various control devices. It is also necessary to install additional display screens in the cabin, which also causes a space penalty for the available passenger space.
In many cases such systems are over-dimensioned, or simply provide more informational capabilities than are required. For example, on short-haul flights, there is often barely time to sensibly utilize such a system. Moreover, relatively small commercial aircraft are typically used for such short-haul flights, and the additional weight and space penalty of such known information systems lead to a significant reduction of the total available load capacity, which leads to an economic penalty in the operation of the aircraft. It is thus essentially not economically possible to utilize such complex inflight entertainment systems with additional monitors and relatively heavy devices and components in such situations, e.g. short flights or relatively small aircraft.